What is the current status on super strings?

how serious is this theory? has it been used to define GR or SR yet or even parts of it?

it is exciting, actualy, because as a student of Mathmatics with an intrest in physics, I have come to think that a theory of the universe that allows for mathmatical solutions dealling with infinity are inherently flawed at those points.

just like newton's theories were shown to be flawed when maxwell applied them to magnatism and found that they had results that were inconsistent with what was observable, we have seen that GR has the same limitations, where as QM is much more robust.

I am confident that when we can explain GR in terms of some form of Quantum effects that we will see that all those infinities are not really there, though the barriors those infinities present are most certainly in existence, they will probably be explainable through a more advanced version of the uncertainty principle.

Superstrings has made baby steps in describing general relativity. They have a graviton which behaves much like Einstein's curvature tensor, but they haven't succeeded in making their theory background independent, which has gradually grown into a criterion for general relativity wannnabes that even the superstring community now acknowledges.

A big success was the superstring calculation of the Hawking-Beckenstein entropy of a black hole. They reproduced the numbers that Hawking and Beckenstein got (those two used a half-and-half "semiclassical" approach), and it's important to state that they did it with true and proper thermodynamic state counting. The only bad news is that this wonderful result is limited to a particular class of black holes, "extremal" black holes that have the most electric charge they can hold (or so I understand the distinction. If someone has a better definition, perhaps they will contribute it).

String physics still hasn't produced any results testable by experiment or astronomical observation. Nor has it succeeded in completely defining its non-perturbative part, M-theory. Work goes on.

I don't believe GR has a class for "extremal" black holes. In GR black holes are characterized by their angular momentum, mass, and charge. I am not sure, but I think the classification as extremal may bring in quantum considerations.